Between the Great War and Pearl Harbor, conservative labor leaders declared themselves America's "first line of defense" against Communism. In her new book Commonsense Anticommunism, historian Jennifer Luff argues that the AFL's "commonsense anticommunism" tried to steer a middle course between the American Legion and the American Civil Liberties Union, defending unions while condemning communism. The outcome of that effort, she argues, shaped American labor politics in ways we continue to grapple with today.